Center of mass quantization of excitons in ${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Cd}}_{\mathit{x}}$Se/ZnSe quantum-wells

Absorption and photoluminescence studies of ${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Cd}}_{\mathit{x}}$Se/ZnSe quantum wells, with well thicknesses at the crossover between two- and three-dimensional exciton behaviors, show clear evidence of quantization of the exciton-polariton center-of-mass motion. A thin-slab variational wave function model is used to reproduce the energy and the dispersion of the center-of-mass states. © 1996 The American Physical Society.